Method of and device for filling an automatically discharging centrifuge drum

ABSTRACT

A centrifuge drum and a method of filling an automatically discharging centrifuge drum with a mixture of liquids that is to be separated. The mixture is introduced through an intake pipe and a header. The header&#39;s intake section communicates with a stack of disks through openings in the header&#39;s base. The base is provided with radial supply channels. Channels at the center of the stack divert the separated lighter liquid phase into a diversion chamber and channels at the periphery of the stack divert the separated heavier liquid phase into another diversion chamber. The drum is charged with an auxiliary liquid obtained from a lower section of the base up to a radially inward level that covers the intake openings into the supply channel in an upper section of the base of the foot. The mixture is then introduced at full power through both sections of the base.

BACKGROUND OF THE INVENTION

The present invention concerns a method of filling an automaticallydischarging centrifuge drum with a mixture of liquids that is to beseparated. The mixture is introduced through an intake pipe and aheader. The header's intake section communicates with a stack of disksthrough openings in the header's base. The base is provided with radialsupply channels. Channels at the center of the stack divert theseparated lighter liquid phase into a diversion chamber, and channels atthe periphery of the stack divert the separated heavier liquid phaseinto another diversion chamber.

The invention also concerns an automatically discharging centrifuge drumof the type having an intake pipe and a header with an intake sectionthat communicates through openings in the base of the header with astack of disks, wherein the base is provided with radial supplychannels, wherein channels at the center of the stack can divert thelighter liquid phase of the separated mixture into a diversion chamber,and wherein other channels at the periphery of the stack divert theheavier liquid phase into another diversion chamber.

A centrifuge drum for separating mixtures of liquids is known fromGerman 2 313 669 C3 for example. The supply channels in this drum arecreated by ribs below the base of the header that extend into the centerof the intake section. The ribs initiate spontaneous acceleration on thepart of the incoming mixture to the same angular speed as that of thedrum. The unavoidable impact can be detrimental to sensitive mixtures.

Such mixtures can be particularly stressed when the ribs or intakeopenings are not covered by the liquid. Once the ribs are below thelevel of the liquid, entrainment will be as extensively careful aspossible due to liquid friction. Such a drum can of course be designedto ensure that the ribs or openings will be covered by liquid duringactual operation, but they will still be uncovered while the drum isbeing charged at the commencement of the separation process or once thedrum has discharged, when they will have the aforesaid deleteriouseffect on the product.

This situation is particularly unacceptable with very precious andimpact-sensitive products, from the separation of blood plasma forexample. In this case the discharged plasma will remain tinged with redfor 30 seconds, a sign of undesirable hemolysis due to impact on thecells.

SUMMARY OF THE INVENTION

The object of the present invention is a method of charging a centrifugedrum wherein the mixture of liquids will not be detrimentally affectedby channels or ribs not covered by liquid.

This object is attained in a method in accordance with the presentinvention wherein, in the following sequence,

a) the drum is charged with an auxiliary liquid obtained from a lowersection of the base of the header up to a level radially inward of theintake openings into that section,

b) the mixture of liquids is introduced at reduced power through thelower section of the base up to a radially inward level that covers theintake openings into the supply channel in an upper section of the baseof the foot, and

c) the mixture is introduced at full power through both sections of thebase.

The initially introduced auxiliary liquid will cover the intake openingsinto the supply channel in the lower section of the base of the headerbefore the impact-sensitive material is introduced into that section atreduced power and gently accelerated. The lower section willsimultaneously charge to a liquid level radially inward of the intakeopenings into the supply channel in the upper section. The level ofliquid in the upper section will simultaneously be displaced radiallyinward until it covers the intake openings in that section. Since allthe intake openings in the header will now be covered with liquid,separation can commence at full power with no detriment to the product.

The auxiliary liquid in one advantageous embodiment of the presentinvention is saltwater. This medium has been particularly proven forseparating blood.

The object of the present invention is also attained in a centrifugedrum for carrying out the method. The drum has the base divided into anupper section and a lower section that communicate at the periphery andwherein intake openings in the supply channels in the upper section ofthe base are situated radially inward of intake openings in the supplychannels in the lower section of the base and the intake pipe opens intothe lower section. Simultaneous displacement of the levels of liquid inthe upper and lower sections is enabled by the peripheral communicationbetween them.

The intake openings in the lower section in one advantageous embodimentof the drum are situated at a diameter D₂ that is longer than thediameter D₁ at the discharge from the second diversion chamber.Auxiliary liquid discharging from the second diversion chamber is, dueto the communicating action between diameter D₁ and diameter D₂, anindication that the intake openings in the lower section are covered.

The intake openings in the upper section in another advantageousembodiment are situated at a diameter D₄ that is longer than thediameter D₃ at the discharge from the first diversion chamber. Separatedliquid discharging from the first diversion chamber is for the samereason an indication that the intake opening in the upper section arecovered.

One embodiment of a centrifuge drum in accordance with the presentinvention will now be specified along with the method in accordance withthe present invention with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross section of a centrifuge drum according to the presentinvention for carrying out the method according to the presentinvention.

FIG. 2 is a view at II in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The centrifuge drum 1 illustrated in FIGS. 1 and 2 has an intake pipe 2and a header 3 that communicate through an intake section 4 and throughopenings 5 in the base 7 of the header with a stack 8 of disks. Base 7is provided with radial supply channels 6. Channels 9 at the center ofstack 8 divert the lighter liquid phase of the separated mixture into adiversion chamber 10. Other channels 12 at the periphery of stack 8divert the heavier liquid phase into another diversion chamber 13. Base7 is divided into an upper section 14 and a lower section 15. These twosections communicate in the vicinity of openings 5. Intake openings 16in the supply channels 6 in the upper section 14 of the base 7 of header3 are situated radially inward of intake openings 17 in the supplychannels 6 in the lower section 15 of the base. Intake pipe 2 opens intolower section 15. Separated solids are extracted through openings 18 atthe periphery of drum 1 and can be opened and closed by a hydraulicallyactuated cylindrical valve 19.

Drum 1 is initially charged with an auxiliary liquid conveyed intosecond diversion chamber 13 through intake pipe 2, the lower section 15of base 7, a mixture-separating compartment 11, and the channels 12 atthe periphery of stack 8 and out at diameter D₁. A liquid level becomesestablished at this diameter, which is shorter than a diameter D₂ in thevicinity of the intake openings 17 into lower section 15, due to thecommunicating action, which also exists in the vicinity of base 7.Intake openings 17 will accordingly be covered by the auxiliary liquid.The mixture, which is subsequently conveyed to lower section 15, willaccordingly be accelerated by contact with the auxiliary liquid. Toprevent lower section 15 from overflowing, it is now charged at lowerpower, and the liquid levels in both upper section 14 and firstdiversion chamber 10, the chamber that diverts the lighter liquid phase,will be simultaneously displaced radially inward by the separatedlighter liquid phase to a diameter D₃ at the discharge from firstdiversion chamber 10. Since diameter D₃ is smaller than the diameter D₄in the vicinity of the intake openings 16 into upper section 14,openings 16 will also be covered with liquid. Separation can now becarried out at full power without detriment to the product.

Due to the radially inward situation of the intake openings 16 intoupper section 14, they will exert a considerably more powerful liquidpressure, and upper section 14 will dictate the drum's output. The mainpurpose of lower section 15 is to allow drum 1 to be charged withoutimpact. The drum is charged in this way subsequent to every discharge byway of solids-extraction openings 18.

We claim:
 1. A method of filling an automatically discharging centrifugedrum with a mixture of liquids that is to be separated, comprising thesteps of:providing a centrifuge drum having an intake pipe and a headerhaving an intake section in communication with a stack of disks throughopenings in a base of the header, wherein the base of the header isdivided into an upper section and a lower section that communicate inthe vicinity of the openings and wherein the lower section has radialsupply channels and the upper section has radial supply channels,wherein channels at a center of the stack of disks divert separatedlighter liquid phase into a first diversion chamber, wherein channels ata periphery of the stack of disks divert the separated heavier liquidphase into a second diversion chamber, wherein intake openings in theradial supply channels in the upper section of the base of the headerare situated radially inward of intake openings in the radial supplychannels in the lower section of the base of the header and the intakepipe opens into the lower section, charging the drum with an auxiliaryliquid obtained from the lower section of the base of the header up to alevel radially inward of the intake openings into the lower section,thereafter introducing the mixture of liquids at reduced power throughthe lower section of the base of the header up to a radially inwardlevel that covers the intake openings into the radial supply channels inthe upper section of the base of the header, and then introducing themixture at full power through both sections of the base of the header.2. The method as in claim 1, wherein the auxiliary liquid is saltwater.3. An automatically discharging drum comprising: an intake pipe and aheader with an intake section that communicates through openings in abase of the header with a stack of disks, wherein the base of the headeris divided into an upper section and a lower section that communicate ata periphery and wherein the lower section has radial supply channels andthe upper section has radial supply channels, channels at the center ofthe stack of disks for diverting a lighter liquid phase of a separatedmixture into a first diversion chamber, and other channels at aperiphery of the stack of disks for diverting a heavier liquid phaseinto a second diversion chamber, wherein intake openings in the radialsupply channels in the upper section of the base of the header aresituated radially inward of intake openings in the radial supplychannels in the lower section of the base of the header and the intakepipe opens into the lower section and wherein the intake openings in thelower section are situated radially outward of a diameter at a dischargefrom the second diversion chamber.
 4. The centrifuge drum as in claim 3,wherein the intake openings in the upper section are situated radiallyoutward of a diameter at a discharge from the first diversion chamber.5. An automatically discharging drum comprising: an intake pipe and aheader with an intake section that communicates through openings in abase of the header with a stack of disks, wherein the base of the headeris divided into an upper section and a lower section that communicate ata periphery and wherein the lower section has radial supply channels andthe upper section has radial supply channels, channels at the center ofthe stack of disks for diverting a lighter liquid phase of a separatedmixture into a first diversion chamber, and other channels at aperiphery of the stack of disks for diverting a heavier liquid phaseinto a second diversion chamber, wherein intake openings in the radialsupply channels in the upper section of the base of the header aresituated radially inward of intake openings in the radial supplychannels in the lower section of the base of the header and the intakepipe opens into the lower section and wherein the intake openings in theupper section are situated radially outward of a diameter at a dischargefrom the first diversion chamber.